[vtkusers] polyline and appendpolydata problem

[kenichiro yoshimi]

Hi

I tested your code with the following input files as a trial, however
the problem didn't occur.
---indexFile---
3
3
---------------
---pointFile---
0.0 0.0 0.0
0.0 1.0 0.0
0.0 2.0 0.0
1.0 0.0 0.0
1.0 1.0 0.0
1.0 2.0 0.0
---------------

I think you need to firstly check the validity of the input file format.

Thanks a lot

2017-10-21 8:07 GMT+09:00 Elvis Chen <elvis.chen at gmail.com>:
> hi all,
>
> I am working on a 3D surface reconstruction problem.  Think of a 3D laser
> scanner, where I have multiple sets of 3D points (1 set per laser scan
> line).  I would like to visualize them as a set of polylines, 1 polyline per
> scan line.
>
> I wrote the following code to read these data from 2 files. One file is a
> set of 3D points, the other is a text file indicating the number of points
> per scan line.  I then create 1 polyline per scan line, and append them
> together using vtkappendpolydata. I then wrote the results into a .vtk file.
>
> However, visualizing the .vtk file suggests that the beginning of the nth
> scan line is connected to the end of the (n-1)th scan line.  How do I create
> a set of the disconnected polylines?
>
> any help is very much appreciated,
>
> My codes are as following:
>
> #include <vtkSmartPointer.h>
> #include <vtkAppendPolyData.h>
> #include <vtkPoints.h>
> #include <vtkPolyLine.h>
> #include <vtkCellArray.h>
> #include <vtkCellData.h>
> #include <vtkPolyData.h>
> #include <vtkPolyDataWriter.h>
>
> int main ( int argc, char *argv[])
>   {
>
>   ifstream indexFile(argv[1]);
>   ifstream pointFile(argv[2]);
>   int num;
>   double x, y, z;
>   vtkSmartPointer< vtkAppendPolyData > append =
>     vtkSmartPointer< vtkAppendPolyData >::New();
>
>   while (indexFile >> num)
>     {
>     vtkSmartPointer< vtkPoints > points =
>       vtkSmartPointer< vtkPoints >::New();
>     vtkSmartPointer< vtkPolyLine > polyline =
>       vtkSmartPointer< vtkPolyLine >::New();
>
>     polyline->GetPointIds()->SetNumberOfIds(num);
>     for (unsigned int i = 0; i < (unsigned int)num; i++)
>       {
>       pointFile >> x >> y >> z;
>       points->InsertNextPoint(x, y, z);
>       polyline->GetPointIds()->SetId(i, i);
>       }
>
>     vtkSmartPointer< vtkCellArray > cells =
>       vtkSmartPointer< vtkCellArray >::New();
>     cells->InsertNextCell(polyline);
>     vtkSmartPointer< vtkPolyData > polyData =
>       vtkSmartPointer< vtkPolyData >::New();
>     polyData->SetPoints(points);
>     polyData->SetLines(cells);
>     polyData->Modified();
>
>     append->AddInputData(polyData);
>     append->Modified();
>     }
>   indexFile.close();
>   pointFile.close();
>
>   vtkSmartPointer< vtkPolyDataWriter > writer =
>     vtkSmartPointer< vtkPolyDataWriter >::New();
>   writer->SetFileName("test.vtk");
>   writer->SetInputConnection(append->GetOutputPort());
>   writer->Write();
>
>
>   return (0);
>   }
>
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